JP4219721B2 - Manufacturing method of laminate - Google Patents

Description

但し、
Ｆ（ｕ，ｖ）：変換によって得られた関数（パワースペクトル）
ｕ，ｖ：ｘ，ｙ方向の波数
ｆ（ｘ，ｙ）：変換対象の関数（３次元形状データ）
（ｘ，ｙ）：平面座標
【００１３】
ここで、1）原子間力顕微鏡にて３次元形状データを測定した積層体であること、2）３次元形状データをフルスケール３〜６μmにて測定した積層体であること、3）導体層が銅箔であり、絶縁層がポリイミド前駆体樹脂溶液を塗布した後、乾燥・硬化することにより形成されたものであること、4）絶縁層が、導体層に熱圧着された熱可塑性樹脂層及び絶縁フィルムにより形成されたものであること、又は、5）絶縁層が、導体層に熱圧着された熱硬化性樹脂層及び絶縁フィルムにより形成されたものであることは本発明の好ましい態様である。
また、本発明は上記の積層体を用いたことを特徴とするＣＯＦフィルムキャリアテープである。
【００１４】
【発明の実施の形態】
以下、本発明を詳細に説明する。
本発明の積層体は、導体層と絶縁層とから構成される。導体層としては、銅箔層が好ましいので、以下の説明において導体層を銅箔層で代表することがある。導体層は絶縁層の片面のみに設けられていてもよく、また両面に設けられていてもよい。
積層体を構成する導体層としては、導電性の各種金属箔等があるが、銅箔の場合は、圧延銅箔を使用してもよく、電解銅箔を使用してもよい。
【００１５】
導体表面形状を規定する方法として、導体層の絶縁層側表面を各点における高さの値からなる３次元形状データを測定する。測定方法としては、触針式、レーザー顕微鏡、原子間力顕微鏡(ＡＦＭ)などを用いることができる。このうち、ＡＦＭを用いる方法が最も本目的に適する。
【００１６】
測定時のフルスケールは、６μmを超えると表面形状の詳細を計測することができない。また、３μm未満ではフルスケールを超える凹凸が多くなり、不適切である。このため、フルスケールを３μｍから６μｍに設定することで、後の処理に適した三次元形状データが得られる。
【００１７】
３次元形状データは、式１に示される二次元フーリエ変換を行って周波数の関数であるパワースペクトルを算出する。この変換により得られるパワースペクトルは、三次元形状の持つ周期性を、正弦波成分として分解し、その波数と方向性を示す２次元画像として得られる。この２次元画像では、画像の中心からの距離が正弦波の波数を示し、画像の中心からの方向が正弦波の方向性に対応する。
【００１８】
xy平面座標系で定義された関数f(x, y)、すなわち３次元形状データの二次元フーリエ変換は、式１で定義される。ここに、u, vはそれぞれ、x, y方向の波数を示す。F(u, v)は波数ベクトル(u, v)に対応したf(x, y)の空間周波数成分、すなわちフーリエ成分を示す。
【００１９】
二次元フーリエ変換は、市販のソフトウエアで実行することが可能である。その際には、画像はf(x. y)といった連続した関数ではなく、有限な分解能を持つＮ×Ｎ個の画素（ピクセル）のディジタルデータを取り扱い、連続関数を用いた積分ではなく、有限和を用いた式を用いる。この際に用いるディジタルデータは、ディジタルカメラ、ＣＣＤカメラ、スキャナ、光学顕微鏡、金属顕微鏡、レーザー顕微鏡、走査型電子顕微鏡、原子間力顕微鏡等により得ることができる。
【００２０】
二次元フーリエ変換によって得られるパワースペクトルは、画像の中心がuv座標系の原点としている。画像の各点における強度はフーリエ成分の大きさに対応し、原点より近い領域の成分は低周波数成分に対応し、原点より遠い領域の成分は高周波数成分に対応する。原点から最も遠い隅の位置の波数ｈ（1/m）は下記式２で示される。
【数３】

ｈ：波数（1/m）
Ｎ：変換前の画像の画素数 （−）
Ｙ：変換前の画像の実視野幅（ｍ）
例えば、５０μｍ×５０μｍの範囲を５１２ピクセル×５１２ピクセルで撮像し、二次元フーリエ変換して得られる５１２ピクセル×５１２ピクセルのパワースペクトルにおいて、４隅の位置は波数７．２４×１０６、すなわち波長０．１４μｍに相当する。
【００２１】
この二次元画像において、可視光波長に対応する３８０nm〜約７８０nmの正弦波成分の強度にて規定することができるが、特に、位置合わせ装置の光源に含まれる波長であり、ポリイミド等の高分子の吸収が少なく、分散されにくい比較的長波長で、かつ市販ＣＣＤカメラの感度が良好である６００nmに相当する周期性成分の強度をもって規定することで、実用的な透明性を規定できることを見出した。
【００２２】
絶縁層を透過してドライバＩＣチップの配線を認識することが可能な積層体は、６００nmに相当する周期性成分の強度が変換前の表面高さ値１．６μmに相当する強度以下である。また、１．５μm以下が更に好ましい。ここでいう、変換前の表面高さ値１．６μmに相当する強度とは、変換前の三次元形状データをフルスケール２μｍで計測した場合には、変換後の強度で８０％、フルスケールを４μｍで計測した場合には、変換後の強度で４０％、フルスケールを６μｍで計測した場合には、変換後の強度で２７％を示す。
【００２３】
積層体を構成する絶縁層には、ポリイミド前駆体樹脂溶液を塗布した後、乾燥・硬化することにより形成されたもの、熱可塑性樹脂層及び絶縁フィルムにより形成されたもの、熱硬化性樹脂層及び絶縁フィルムにより形成されたもののいずれを用いてもよい。
【００２４】
これらの積層体を構成する絶縁層うち、ポリイミド前駆体樹脂溶液を塗布した後、乾燥・硬化することにより形成されたものが最も適するが、本発明はこれに限定されるものではない。
【００２５】
ポリイミド前駆体樹脂溶液は、公知のジアミンと酸無水物とを溶媒の存在下で重合して製造することができる。
【００２６】
用いられるジアミンとしては、例えば、4,4'-ジアミノジフェニルエーテル、2'-メトキシ4,4'-ジアミノベンズアニリド、1,4-ビス（4-アミノフェノキシ）ベンゼン、1,3-ビス（4-アミノフェノキシ）ベンゼン、2,2'-ビス[4-(4-アミノフェノキシ)フェニル]プロパン、2,2'-ジメチル-4,4'-ジアミノビフェニル、3,3'-ジヒドロキシ-4,4'-ジアミノビフェニル、4,4'ジアミノベンズアニリド等が挙げられる。また、酸無水物としては、例えば、無水ピロメリット酸、3,3'4,4'-ビフェニルテトラカルボン酸二無水物、3,4'3,4'-ビフェニルテトラカルボン酸二無水物、3,3'4,4'-ジフェニルスルフォンテトラカルボン酸二無水物、4,4'-オキシジフタル酸無水物が挙げられる。ジアミン、酸無水物はそれぞれ、その１種のみを使用してもよく２種以上を併用して使用することもできる。
【００２７】
溶媒は、ジメチルアセトアミド、ｎ-メチルピロリジノン、2-ブタノン、ジグライム、キシレン等が挙げられ、1種若しくは2種以上併用して使用することもできる。
【００２８】
ポリイミド系樹脂層は、前駆体状態で銅箔層上に直接塗布して形成することが好ましく、重合された樹脂粘度を５００cps〜３５，０００cpsの範囲とすることが好ましい。塗布された樹脂液は熱処理されるが、熱処理は１００℃〜１５０℃で２分〜４分大気中で熱処理し、その後、真空加熱で室温-340℃-室温処理を９時間ほど行なうことがよい。ポリイミド樹脂層は、単層のみから形成されるものでも、複数層からなるものでもよい。ポリイミド系樹脂層を複数層とする場合、異なる構成成分からなるポリイミド系樹脂層の上に他のポリイミド樹脂を順次塗布して形成することができる。ポリイミド樹脂層が３層以上からなる場合、同一の構成のポリイミド樹脂を２回以上使用してもよい。
【００２９】
本発明の積層板の代表例である銅張り積層板は、上記したように銅箔上にポリイミド樹脂を塗布することにより製造することができるが、１層以上のポリイミドフィルムを銅箔にラミネートして製造することもできる。このように製造された銅張り積層板は銅箔層を片面のみに有する片面銅張り積層板としてもよく、また、銅箔層を両面に有する両面銅張り積層板とすることもできる。両面銅張り積層体は、片面銅張り積層板を形成後、銅箔層を熱プレスにより圧着する方法、２枚の銅箔層間にポリイミドフィルムを挟み熱プレスにより圧着する方法等が挙げられる。
【００３０】
【実施例】
以下、本発明を実施例により更に詳細に説明する。
積層体の作成にあたり、下記４種類の銅箔を準備した。
1）銅箔１：電解銅箔、Ｒｚ1.0μm
2）銅箔２：電解銅箔、Ｒｚ0.8μm
3）銅箔３：圧延銅箔、Ｒｚ2.0μm
4) 銅箔４：銅箔３を５％塩酸水溶液に１分浸漬したサンプル、Ｒｚ2.0μｍ
【００３１】
合成例1
熱電対、攪拌機、窒素導入可能な反応容器に、ｎ-メチルピロリジノンを入れる。この反応容器を容器に入った氷水に浸けた後、反応容器に無水ピロメリット酸（PMDA）を投入し、その後、4,4'-ジアミノジフェニルエーテル、（DAPE）と2'-メトキシ4,4'-ジアミノベンズアニリド(MABA)を投入した。モノマーの投入総量が15wt％で、各ジアミンのモル比率は、MABA:DAPE＝60：40となり、酸無水物とジアミンのモル比が0.98：1.0となるよう投入した。その後、更に攪拌を続け、反応容器内の温度が、室温から±5℃の範囲となった時に反応容器を氷水から外し、更に室温のまま3時間攪拌を続けた。得られたポリアミック酸の溶液粘度は、15,000cpsであった。
【００３２】
合成例２
ｎ-メチルピロリジノンを入れた反応容器を氷水に浸けた後、反応容器にPMDA/3,4'3,4'-ビフェニルテトラカルボン酸二無水物(BTDA)を投入し、その後、4,4'-ジアミノジフェニルエーテル(DAPE)を投入した。モノマーの投入総量が15wt％で、各酸無水物のモル比率は、BTDA:PMDA＝70:30となり、酸無水物とジアミンのモル比が1.03：1.0となるよう投入した。その後、更に攪拌を続け、反応容器内の温度が、室温から±5℃の範囲となった時に反応容器を氷水から外し、更に室温のまま3時間攪拌を続けた。得られたポリアミック酸の溶液粘度は、3,200cpsであった。
【００３３】
合成例3
ｎ-メチルピロリジノンを入れた反応容器を氷水に浸けた後、反応容器に3,3'4,4'-ジフェニルスルフォンテトラカルボン酸二無水物(DSDA)、PMDAを投入し、その後、1,3-ビス（4-アミノフェノキシ）ベンゼン(TPE‐R)を投入した。モノマーの投入総量が15wt％で、各酸無水物のモル比率は、DSDA:PMDA＝90:10となり、酸無水物とジアミンのモル比が1.03：1.0となるよう投入した。その後、更に攪拌を続け、反応容器内の温度が、室温から±5℃の範囲となった時に反応容器を氷水から外し、更に室温のまま3時間攪拌を続けた。得られたポリアミック酸の溶液粘度は、3,200cpsであった。
【００３４】
実施例１
銅箔として、銅箔１を使用した。この銅箔の表面を原子間力顕微鏡（デジタルインスツルメンツ製走査型プローブ顕微鏡NanoScope）を用い、50μm方形の範囲を、フルスケール4μm、256階調にて形状計測した。一階調は0.0156μｍに相当する。
得られた画像を市販の汎用画像処理ソフトウエアにて二次元フーリエ変換しパワースペクトルを得た。このパワースペクトルより、波長600nmに相当する位置の強度を測定したところ、256階調中、93階調に相当し、強度は36％であった。またこれは、変換前の形状データのフルスケールが4μmであることから、1.45μmに相当する。
【００３５】
この電解銅箔上に合成例１から３のポリアミック酸溶液を塗布、乾燥を繰り返し、銅箔層上にポリイミド前駆体樹脂層が形成された積層体を得た。この積層体を340℃で、8時間かけて熱処理し、ポリイミド厚み40μmの片面銅箔の積層体を得た。
この積層体を塩化第二鉄水溶液にてエッチングし、40μmの絶縁層フィルムを得た。市販ボンダー機（新川（株）製ILT−110）を用いて、このフィムルと試験用に準備したドライバＩＣチップを100μmの距離を保った状態で保持し、ボンダー機に装備された位置合わせ用のＣＣＤカメラを用いて、模擬チップ上の200μmの大きさの検査パターンを観察したところ、良好な画像が得られた。
【００３６】
比較例１
銅箔として、銅箔２を使用した。実施例１と同様に表面形状を測定したところ、波長600nmに相当する強度は、256階調中、108階調に相当し、強度としては42％であった。またこれは、変換前の形状データのフルスケールが4μmであることから、1.68μmに相当する。
上記電解銅箔２を実施例１と同様に、積層体化し、フィルム化し、フィルムを透過してＩＣチップを観察したところ、画像は認識できなかった。
【００３７】
比較例２
銅箔として、銅箔１を使用した。対象波長を300nmとする以外は、実施例１と同様に表面形状を測定したところ、波長300nmに相当する強度は、256階調中、85階調に相当し、強度としては33％であった。またこれは、変換前の形状データのフルスケールが4μmであることから、1.32μmに相当する。
【００３８】
比較例３
銅箔として、銅箔２を使用し、比較例２と同様に表面形状を測定したところ、波長300nmに相当する強度は、256階調中、85階調に相当し、強度としては33％であった。またこれは、変換前の形状データのフルスケールが4μmであることから、1.32μmに相当する。
【００３９】
比較例４
銅箔として、銅箔３を使用し、実施例１と同様に表面形状を測定したところ、波長600nmに相当する強度は、256階調中、119階調に相当し、強度としては46％であった。またこれは、変換前の形状データのフルスケールが4μmであることから、1.86μmに相当する。
この銅箔３を実施例１と同様に、積層体化し、フィルム化し、フィルムを透過してＩＣチップを観察したところ、画像は認識できなかった。
【００４０】
実施例２
銅箔として、銅箔４を使用し、実施例１と同様に表面形状を測定したところ、波長600nmに相当する強度は、256階調中、90階調に相当し、強度としては35％であった。またこれは、変換前の形状データのフルスケールが4μmであることから、1.41μmに相当する。
この酸洗済み圧延銅箔４を実施例１と同様に、積層体化し、フィルム化し、フィルムを透過してＩＣチップを観察したところ、良好な画像が得られた。
結果をまとめて表１に示す。
【００４１】
【表１】

【００４２】
【発明の効果】
絶縁層を透過してドライバＩＣチップの配線を認識することが可能となり、導体と絶縁体の間の接着力が高く、耐エレクトロマイグレーション性に優れた積層体の製造を可能とする。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a copper-clad laminate for a flexible printed circuit board on which an electronic component such as an IC or LSI is mounted.
[0002]
[Prior art]
A TAB method (tape automated bonding) in which a driver IC is mounted on a tape carrier has been conventionally used in the electronic industry using a liquid crystal display element (LCD).
[0003]
Further, COF (chip-on-film) in which a bare IC chip is directly mounted on a film carrier tape has been developed as a mounting method for mounting at a higher density in a smaller space.
[0004]
Since the flexible printed circuit board (FPC) used for this COF does not have a device hole that has been used in the TAB method, when measuring the relative position during chip mounting, the driver IC chip is transmitted through the insulating layer. It is necessary to recognize the wiring.
[0005]
As a laminated body used for such FPC for COF, there is a laminated body obtained by sputtering an adhesion reinforcing layer such as nickel on an insulating film such as a polyimide film and then performing copper plating. In such a copper plating laminate, since the polyimide film is relatively transparent, alignment during IC mounting is easy, but the adhesion between the conductor and the insulator is low, and the electromigration resistance is poor. There is a problem.
[0006]
As a laminate without such a problem, there are a casting type in which a polyimide film is laminated on a copper foil by a coating method, and a thermocompression bonding type in which an insulating film is thermocompression bonded to the copper foil via a thermoplastic resin or a thermosetting resin. There is a laminate.
[0007]
However, in the casting type or thermocompression type laminate, the surface of the insulating layer exposed when the copper foil is removed by etching diffuses light, and the wiring of the driver IC chip cannot be recognized through the insulating layer. There was a problem.
[0008]
Against this background, a method for producing a copper foil with a small roughness has been proposed. Japanese Patent Laid-Open No. 2002-73188 discloses a method for polishing an electrolytically deposited surface. Japanese Unexamined Patent Application Publication No. 2002-161394 discloses a method for manufacturing a roughened layer of copper foil. Japanese Patent Application Laid-Open No. 09-143785 discloses a low-roughness copper foil having a small Rz with a mercapto compound. Japanese Unexamined Patent Application Publication No. 2003-23046 discloses an insulator having a prescribed light transmittance.
[Patent Document 1]
JP 2002-73188 A [Patent Document 2]
JP 2002-161394 A [Patent Document 3]
Japanese Patent Laid-Open No. 09-143785 [Patent Document 4]
Japanese Patent Laid-Open No. 2003-23046
In these techniques, as a method for defining the roughness of the copper foil surface, JIS B 0601-1994 “Definition and Display of Surface Roughness”, calculated from a stylus-type roughness meter, etc. Rz defined in the definition of average roughness (Rz) is often used. However, this Rz is incomplete to define the correlation with optical characteristics such as optical scattering, and in some cases, it is actually impossible to recognize the wiring of the driver IC chip. For this reason, in the low-roughness copper foil, the development of a laminate having a conductor surface shape defined by optical characteristics has been desired.
[0010]
[Problems to be solved by the invention]
An object of the present invention is to provide a laminate that can recognize a wiring of a driver IC chip through an insulating layer, has high adhesion between a conductor and an insulator, and has excellent electromigration resistance. .
[0011]
[Means for Solving the Problems]
As a result of investigations to solve the above problems, the present inventors have found that the above-mentioned problems can be solved by using a conductor layer such as a copper foil constituting the laminated body having specific characteristics. The present invention has been completed.
[0012]
That is, in the present invention, the surface on the insulating layer side of a conductor layer made of rolled copper foil or electrolytic copper foil is measured with an atomic force microscope and three-dimensional shape data is measured at a full scale of 3 to 6 μm. Is measured as three-dimensional shape data consisting of values, a power spectrum as a function of frequency is calculated by performing a two-dimensional Fourier transform represented by the following formula 1, and the intensity of the frequency corresponding to 600 nm is the surface height value before the conversion. A flexible printed circuit board having a structure in which a conductive layer and a light-transmissive insulating layer are laminated, wherein a conductive layer having a strength equal to or less than 1.6 μm is selected and an insulating layer is laminated on the conductive layer It is a manufacturing method of the laminated body for use .
According to the manufacturing method described above, the conductor layer and the insulating layer are laminated, and the insulating layer side surface of the conductor layer is measured as three-dimensional shape data consisting of height values at each point. A power spectrum that is a function of frequency is calculated by performing the two-dimensional Fourier transform shown, and a laminated body in which the intensity of the frequency corresponding to 600 nm is equal to or less than the intensity corresponding to the surface height value of 1.6 μm before the conversion is obtained. Can do.
[Expression 2]

However,
F (u, v): function obtained by conversion (power spectrum)
u, v: wave number f (x, y) in x, y direction: function to be converted (three-dimensional shape data)
(X, y): plane coordinates
Here, 1) a laminate obtained by measuring three-dimensional shape data with an atomic force microscope, 2) a laminate obtained by measuring three-dimensional shape data at a full scale of 3 to 6 μm, and 3) a conductor layer. Is a copper foil, and the insulating layer is formed by applying a polyimide precursor resin solution, followed by drying and curing; 4) a thermoplastic resin layer in which the insulating layer is thermocompression bonded to the conductor layer It is a preferable embodiment of the present invention that the insulating layer is formed of a thermosetting resin layer and an insulating film that are thermocompression bonded to the conductor layer. is there.
Moreover, this invention is a COF film carrier tape characterized by using the above laminate.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The laminate of the present invention is composed of a conductor layer and an insulating layer. Since a copper foil layer is preferable as the conductor layer, the conductor layer may be represented by a copper foil layer in the following description. The conductor layer may be provided only on one side of the insulating layer, or may be provided on both sides.
As the conductor layer constituting the laminate, there are various conductive metal foils, but in the case of copper foil, rolled copper foil or electrolytic copper foil may be used.
[0015]
As a method for defining the conductor surface shape, three-dimensional shape data consisting of height values at respective points on the insulating layer side surface of the conductor layer is measured. As a measuring method, a stylus type, a laser microscope, an atomic force microscope (AFM), or the like can be used. Of these, the method using AFM is most suitable for this purpose.
[0016]
If the full scale at the time of measurement exceeds 6 μm, the details of the surface shape cannot be measured. On the other hand, if the thickness is less than 3 μm, irregularities exceeding full scale increase, which is inappropriate. Therefore, by setting the full scale from 3 μm to 6 μm, three-dimensional shape data suitable for later processing can be obtained.
[0017]
The three-dimensional shape data is subjected to the two-dimensional Fourier transform shown in Equation 1 to calculate a power spectrum that is a function of frequency. The power spectrum obtained by this conversion is obtained as a two-dimensional image indicating the wave number and directionality by decomposing the periodicity of the three-dimensional shape as a sine wave component. In this two-dimensional image, the distance from the center of the image indicates the wave number of the sine wave, and the direction from the center of the image corresponds to the directionality of the sine wave.
[0018]
The function f (x, y) defined in the xy plane coordinate system, that is, the two-dimensional Fourier transform of the three-dimensional shape data is defined by Equation 1. Here, u and v indicate wave numbers in the x and y directions, respectively. F (u, v) represents a spatial frequency component of f (x, y) corresponding to the wave vector (u, v), that is, a Fourier component.
[0019]
The two-dimensional Fourier transform can be executed with commercially available software. In that case, the image is not a continuous function such as f (x. Y), but digital data of N × N pixels (pixels) having a finite resolution is handled. The formula using the sum is used. Digital data used at this time can be obtained by a digital camera, a CCD camera, a scanner, an optical microscope, a metal microscope, a laser microscope, a scanning electron microscope, an atomic force microscope, or the like.
[0020]
In the power spectrum obtained by the two-dimensional Fourier transform, the center of the image is the origin of the uv coordinate system. The intensity at each point of the image corresponds to the magnitude of the Fourier component, the component in the region near the origin corresponds to the low frequency component, and the component in the region far from the origin corresponds to the high frequency component. The wave number h (1 / m) at the corner farthest from the origin is expressed by the following equation 2.
[Equation 3]

h: Wave number (1 / m)
N: Number of pixels of image before conversion (-)
Y: Actual field width of the image before conversion (m)
For example, in a power spectrum of 512 pixels × 512 pixels obtained by imaging a range of 50 μm × 50 μm with 512 pixels × 512 pixels and two-dimensional Fourier transform, the positions of the four corners have a wavenumber of 7.24 × 106, that is, a wavelength of 0 .Corresponding to 14 μm.
[0021]
In this two-dimensional image, it can be defined by the intensity of a sine wave component of 380 nm to about 780 nm corresponding to the visible light wavelength. In particular, it is a wavelength included in the light source of the alignment device, and is a polymer such as polyimide. It has been found that practical transparency can be defined by defining the intensity of a periodic component corresponding to 600 nm, which has a relatively long wavelength that is difficult to disperse, is difficult to disperse, and has a good sensitivity of a commercially available CCD camera. .
[0022]
In the laminate that can recognize the wiring of the driver IC chip through the insulating layer, the intensity of the periodic component corresponding to 600 nm is equal to or less than the intensity corresponding to the surface height value 1.6 μm before conversion. Further, 1.5 μm or less is more preferable. Here, the intensity corresponding to the surface height value before conversion of 1.6 μm means that when the three-dimensional shape data before conversion is measured at 2 μm full scale, the intensity after conversion is 80%, and the full scale is When measured at 4 μm, the intensity after conversion is 40%, and when full scale is measured at 6 μm, the intensity after conversion is 27%.
[0023]
The insulating layer constituting the laminate is formed by applying a polyimide precursor resin solution, followed by drying and curing, a thermoplastic resin layer and an insulating film, a thermosetting resin layer, and Any of those formed of an insulating film may be used.
[0024]
Of the insulating layers constituting these laminates, those formed by applying a polyimide precursor resin solution and then drying and curing are most suitable, but the present invention is not limited to this.
[0025]
The polyimide precursor resin solution can be produced by polymerizing a known diamine and acid anhydride in the presence of a solvent.
[0026]
Examples of the diamine used include 4,4′-diaminodiphenyl ether, 2′-methoxy 4,4′-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4- Aminophenoxy) benzene, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxy-4,4 ' -Diaminobiphenyl, 4,4′diaminobenzanilide and the like. Examples of the acid anhydride include pyromellitic anhydride, 3,3′4,4′-biphenyltetracarboxylic dianhydride, 3,4′3,4′-biphenyltetracarboxylic dianhydride, 3 , 3'4,4'-diphenylsulfone tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride. Each of the diamine and acid anhydride may be used alone or in combination of two or more.
[0027]
Examples of the solvent include dimethylacetamide, n-methylpyrrolidinone, 2-butanone, diglyme, xylene and the like, and they can be used alone or in combination of two or more.
[0028]
The polyimide resin layer is preferably formed by directly coating on the copper foil layer in a precursor state, and the polymerized resin viscosity is preferably in the range of 500 cps to 35,000 cps. The applied resin solution is heat-treated, and heat treatment is preferably performed in air at 100 ° C. to 150 ° C. for 2 to 4 minutes, and then vacuum heating is performed at room temperature-340 ° C. for about 9 hours. . The polyimide resin layer may be formed of only a single layer or may be formed of a plurality of layers. In the case where a plurality of polyimide resin layers are used, other polyimide resins can be sequentially formed on a polyimide resin layer made of different components. When the polyimide resin layer is composed of three or more layers, the polyimide resin having the same configuration may be used twice or more.
[0029]
A copper-clad laminate, which is a representative example of the laminate of the present invention, can be produced by applying a polyimide resin on a copper foil as described above, but one or more polyimide films are laminated on the copper foil. Can also be manufactured. The copper-clad laminate thus produced may be a single-sided copper-clad laminate having a copper foil layer only on one side, or a double-sided copper-clad laminate having a copper foil layer on both sides. Examples of the double-sided copper-clad laminate include a method of forming a single-sided copper-clad laminate and then crimping the copper foil layer by hot pressing, a method of sandwiching a polyimide film between two copper foil layers, and crimping by hot pressing.
[0030]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
In creating the laminate, the following four types of copper foils were prepared.
1) Copper foil 1: Electrolytic copper foil, Rz1.0μm
2) Copper foil 2: Electrolytic copper foil, Rz0.8μm
3) Copper foil 3: Rolled copper foil, Rz 2.0 μm
4) Copper foil 4: Sample obtained by immersing copper foil 3 in 5% aqueous hydrochloric acid for 1 minute, Rz 2.0 μm
[0031]
Synthesis example 1
N-methylpyrrolidinone is placed in a thermocouple, a stirrer, and a reaction vessel into which nitrogen can be introduced. After immersing this reaction vessel in ice water contained in the vessel, pyromellitic anhydride (PMDA) was added to the reaction vessel, and then 4,4'-diaminodiphenyl ether, (DAPE) and 2'-methoxy 4,4 ' -Diaminobenzanilide (MABA) was introduced. The total monomer charge was 15 wt%, the molar ratio of each diamine was MABA: DAPE = 60: 40, and the molar ratio of acid anhydride to diamine was 0.98: 1.0. Thereafter, stirring was further continued, and when the temperature in the reaction vessel was within the range of room temperature to ± 5 ° C., the reaction vessel was removed from ice water, and stirring was further continued for 3 hours at room temperature. The solution viscosity of the obtained polyamic acid was 15,000 cps.
[0032]
Synthesis example 2
After soaking the reaction vessel containing n-methylpyrrolidinone in ice water, PMDA / 3,4'3,4'-biphenyltetracarboxylic dianhydride (BTDA) is charged into the reaction vessel, and then 4,4 ' -Diaminodiphenyl ether (DAPE) was added. The total amount of monomers charged was 15 wt%, the molar ratio of each acid anhydride was BTDA: PMDA = 70: 30, and the molar ratio of acid anhydride to diamine was 1.03: 1.0. Thereafter, stirring was further continued, and when the temperature in the reaction vessel was within the range of room temperature to ± 5 ° C., the reaction vessel was removed from ice water, and stirring was further continued for 3 hours at room temperature. The solution viscosity of the obtained polyamic acid was 3,200 cps.
[0033]
Synthesis example 3
After immersing the reaction vessel containing n-methylpyrrolidinone in ice water, 3,3'4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) and PMDA are added to the reaction vessel, and then 1,3 -Bis (4-aminophenoxy) benzene (TPE-R) was added. The total amount of monomers charged was 15 wt%, the molar ratio of each acid anhydride was DSDA: PMDA = 90: 10, and the molar ratio of acid anhydride to diamine was 1.03: 1.0. Thereafter, stirring was further continued, and when the temperature in the reaction vessel was within the range of room temperature to ± 5 ° C., the reaction vessel was removed from ice water, and stirring was further continued for 3 hours at room temperature. The solution viscosity of the obtained polyamic acid was 3,200 cps.
[0034]
Example 1
Copper foil 1 was used as the copper foil. Using an atomic force microscope (Scanning Probe Microscope NanoScope manufactured by Digital Instruments), the shape of the surface of the copper foil was measured at a full scale of 4 μm and 256 gradations. One gradation corresponds to 0.0156 μm.
The obtained image was subjected to two-dimensional Fourier transform using commercially available general-purpose image processing software to obtain a power spectrum. From this power spectrum, the intensity at a position corresponding to a wavelength of 600 nm was measured. As a result, it was equivalent to 93 gradations out of 256 gradations, and the intensity was 36%. This corresponds to 1.45 μm because the full scale of the shape data before conversion is 4 μm.
[0035]
The polyamic acid solutions of Synthesis Examples 1 to 3 were applied on this electrolytic copper foil and dried repeatedly to obtain a laminate in which a polyimide precursor resin layer was formed on the copper foil layer. This laminated body was heat-treated at 340 ° C. for 8 hours to obtain a single-sided copper foil laminated body having a polyimide thickness of 40 μm.
This laminate was etched with an aqueous ferric chloride solution to obtain a 40 μm insulating layer film. Using a commercially available bonder machine (ILT-110, manufactured by Shinkawa Co., Ltd.), this film and the driver IC chip prepared for the test are held at a distance of 100 μm and used for alignment equipped on the bonder machine. When an inspection pattern having a size of 200 μm on the simulated chip was observed using a CCD camera, a good image was obtained.
[0036]
Comparative Example 1
Copper foil 2 was used as the copper foil. When the surface shape was measured in the same manner as in Example 1, the intensity corresponding to the wavelength of 600 nm was equivalent to 108 gradations out of 256 gradations, and the intensity was 42%. This corresponds to 1.68 μm because the full scale of the shape data before conversion is 4 μm.
As in Example 1, the electrolytic copper foil 2 was laminated, formed into a film, passed through the film, and the IC chip was observed. As a result, no image could be recognized.
[0037]
Comparative Example 2
Copper foil 1 was used as the copper foil. The surface shape was measured in the same manner as in Example 1 except that the target wavelength was 300 nm. The intensity corresponding to the wavelength 300 nm was equivalent to 85 gradations out of 256 gradations, and the intensity was 33%. . This corresponds to 1.32 μm because the full scale of the shape data before conversion is 4 μm.
[0038]
Comparative Example 3
When copper foil 2 was used as the copper foil and the surface shape was measured in the same manner as in Comparative Example 2, the intensity corresponding to the wavelength of 300 nm was equivalent to 85 gradations in 256 gradations, and the intensity was 33%. there were. This corresponds to 1.32 μm because the full scale of the shape data before conversion is 4 μm.
[0039]
Comparative Example 4
When copper foil 3 was used as the copper foil and the surface shape was measured in the same manner as in Example 1, the intensity corresponding to the wavelength of 600 nm corresponds to 119 gradations out of 256 gradations, and the intensity was 46%. there were. This corresponds to 1.86 μm because the full scale of the shape data before conversion is 4 μm.
When this copper foil 3 was laminated and film-formed in the same manner as in Example 1 and the IC chip was observed through the film, no image could be recognized.
[0040]
Example 2
When copper foil 4 was used as the copper foil and the surface shape was measured in the same manner as in Example 1, the intensity corresponding to the wavelength of 600 nm was equivalent to 90 gradations in 256 gradations, and the intensity was 35%. there were. This corresponds to 1.41 μm because the full scale of the shape data before conversion is 4 μm.
When this pickled rolled copper foil 4 was laminated in the same manner as in Example 1 to form a film, and the IC chip was observed through the film, a good image was obtained.
The results are summarized in Table 1.
[0041]
[Table 1]

[0042]
【The invention's effect】
It is possible to recognize the wiring of the driver IC chip through the insulating layer, and it is possible to manufacture a laminate having high adhesion between the conductor and the insulator and excellent in electromigration resistance.

Claims (1)

Three-dimensional shape consisting of height values at each point by measuring the surface of the insulating layer side of the conductor layer made of rolled copper foil or electrolytic copper foil with an atomic force microscope and measuring the three-dimensional shape data at a full scale of 3-6 μm. Measured as data, a two-dimensional Fourier transform represented by the following formula 1 is performed to calculate a power spectrum as a function of frequency, and the intensity of the frequency corresponding to 600 nm corresponds to the surface height value before conversion of 1.6 μm. Production of a laminate for a flexible printed circuit board having a structure in which a conductive layer and a light-transmissive insulating layer are laminated, wherein a conductive layer having a strength or lower is selected and an insulating layer is laminated on the conductive layer. Method.

F (u, v): function obtained by conversion (power spectrum)
u, v: wave numbers in x and y directions f (x, y): function to be converted (three-dimensional shape data)
(X, y): plane coordinates